atof – cppreference.com

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definiert in Header `<stdlib.h>`

`double atof( const char* str );`

Legt eine Fließkommazahl in einem Byte String, auf den str .

Original:

Interprets an floating point value in a byte string pointed to by str.

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Funktion verwirft alle Whitespace-Zeichen (wie std::isspace() bestimmt) bis zum ersten Nicht-Whitespace-Zeichen gefunden wird. Dann dauert es so viele Zeichen wie möglich, um eine gültige Gleitkomma-Darstellung bilden und wandelt sie in Fließkommazahl. Der gültige Gleitkommawert kann eine der folgenden sein:

Original:

Function discards any whitespace characters (as determined by std::isspace()) until first non-whitespace character is found. Then it takes as many characters as possible to form a valid floating point representation and converts them to floating point value. The valid floating point value can be one of the following:

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Gleitpunktberechnungen Ausdruck. Es besteht aus folgenden Teilen:
Original:
decimal floating point expression. It consists of the following parts:
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(optional) Plus-oder Minuszeichen
Original:
(optional) plus or minus sign
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nichtleere Folge von Dezimalziffern gegebenenfalls ein Dezimalzeichen (definiert Mantisse)
Original:
nonempty sequence of decimal digits optionally containing a decimal point character (defines significand)
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(optional) e oder E folgte mit optional Minus-oder Pluszeichen und nichtleere Folge von Dezimalziffern (definiert Exponent)
Original:
(optional) e or E followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
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binäre Fließkomma-Ausdruck. Es besteht aus folgenden Teilen:
Original:
binary floating point expression. It consists of the following parts:
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(optional) Plus-oder Minuszeichen
Original:
(optional) plus or minus sign
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0x or 0X
nichtleere Folge von Hexadezimalziffern gegebenenfalls ein Dezimalzeichen (definiert Mantisse)
Original:
nonempty sequence of hexadecimal digits optionally containing a decimal point character (defines significand)
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(optional) p oder P folgte mit optional Minus-oder Pluszeichen und nichtleere Folge von Hexadezimalziffern (definiert Exponent)
Original:
(optional) p or P followed with optional minus or plus sign and nonempty sequence of hexadecimal digits (defines exponent)
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infinity Ausdruck. Es besteht aus folgenden Teilen:
Original:
infinity expression. It consists of the following parts:
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(optional) Plus-oder Minuszeichen
Original:
(optional) plus or minus sign
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INF oder INFINITY ignorieren Fall
Original:
INF or INFINITY ignoring case
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not-a-number Ausdruck. Es besteht aus folgenden Teilen:
Original:
not-a-number expression. It consists of the following parts:
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(optional) Plus-oder Minuszeichen
Original:
(optional) plus or minus sign
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NAN oder NAN( char_sequence ) ignorieren Fall des NAN Teil. Char_sequence kann nur alphanumerische Zeichen enthalten. Das Ergebnis ist ein ruhiger NaN Gleitkommawert .
Original:
NAN or NAN(char_sequence) ignoring case of the NAN part. char_sequence can only contain alphanumeric characters. The result is a quiet NaN floating point value.
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Parameter

str

Zeiger auf die null-terminierte Byte-String interpretiert werden

Original:

pointer to the null-terminated byte string to be interpreted

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Rückgabewert

double entsprechenden Wert auf den Inhalt der str auf Erfolg. Wenn der konvertierte Wert fällt außerhalb des Bereichs der Rückgabetyp ist der Rückgabewert undefiniert. Wenn keine Umwandlung durchgeführt werden kann, wird zurückgegeben 0.0 .

Original:

double value corresponding to the contents of str on success. If the converted value falls out of range of the return type, the return value is undefined. If no conversion can be performed, 0.0 is returned.

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Beispiel

Siehe auch


	wandelt ein Byte String in eine Gleitkommazahl Original: converts a byte string to a floating point value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktion) [edit]